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A Facile and Specific Approach to New Liquid Chromatography Adsorbents Obtained by Ionic Self‐Assembly
Author(s) -
Qiu Hongdeng,
Mallik Abul K.,
Takafuji Makoto,
Ihara Hirotaka
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201100137
Subject(s) - ionic liquid , selectivity , chemistry , bromide , thermogravimetric analysis , surface modification , adsorption , diffuse reflectance infrared fourier transform , potassium bromide , high performance liquid chromatography , ionic bonding , elution , ion exchange , chromatography , organic chemistry , catalysis , ion , photocatalysis
A new ionic‐liquid monomer, 1‐vinyl‐3‐octadecylimidazolium bromide ([C 18 VIm]Br), was prepared and polymerized on porous silica particles by means of a surface‐initiated radical chain‐transfer reaction. Further modification for functionalization was performed through the exchange of counteranions from bromide to methyl orange (MO). Two new silica–poly(octadecylimidazolium) (Sil‐PImC 18 ) hybrid materials (Sil‐PImC 18 ‐Br and Sil‐PImC 18 ‐MO) were synthesized and characterized by elemental analysis, thermogravimetric analysis, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and solid‐state 13 C CP/MAS NMR spectroscopy. Sil‐PImC 18 ‐MO presented ultra‐high shape selectivity for constrained isomers of polycyclic aromatic hydrocarbons (PAHs) both in reversed‐ and normal‐phase HPLC when used as the stationary phase. Fundamental aspects of the molecular shape selectivity were evaluated by using Standard Reference Material (SRM) 869b; the column selectivity test mixture for liquid chromatography. The impact of this phase was also demonstrated by the separation of SRM 1647e (16 priority pollutant PAHs) and several steroid isomers. Enhanced selectivity could be explained by the highly oriented arrangement between the octadecylimidazolium chain and a rigid segment of MO. These findings may open a new window of research for the design of materials used in chromatographic supports, solid extraction, catalysis, and electrolytes by simple modifications of the counterions in the poly(ionic liquid) analogous phase.